For the first time ever, physicists perform ABRACADABRA, a groundbreaking new experiment to hunt down hypothetical ghost-like particles known as axions.
Axions: What Are They?
About 85 percent of the total known mass of the universe is actually unaccounted for.
Scientists have been searching for this missing mass, which is commonly known as dark matter.
While dark matter should be everywhere — it should make up 85 percent of the universe — scientists have found scant evidence of its existence. It's usually only detected through its interactions with regular matter.
The hypothetical particle axion is a promising dark matter candidate. Invisible and extremely light, axions are expected to be ghost-like with extremely faint interactions with other objects in the universe.
"As dark matter, they shouldn't affect your everyday life," Lindley Winslow, the Jerrold R. Zacharias Career Development Assistant Professor of Physics at MIT, says in a report from the university. "But they're thought to affect things on a cosmological level, like the expansion of the universe and the formation of galaxies we see in the night sky."
Now, Windley is leading the hunt for axions in the first experiment of its kind called the ABRACADABRA: A Broadband/Resonant Approach to Cosmic Axion Detection with an Amplifying B-field Ring Apparatus.
The Search For Axions With ABRACADABRA
It's been theorized that the best way to detect axions is through magnetars, which is a neutron star with a very powerful magnetic field. In the presence of a magnetar, axions are believed to be converted to radio waves, which can be detected by scientists using telescopes.
It is this theory that inspired the MIT-led team to design and carry out their experiment.
In a study published in the journal Physical Review Letters, Windley's team conducted the ABRACADABRA experiment, which involved hanging a donut-shaped magnet in a freezer at a temperature just above absolute zero. If axions exist, a magnetic field should be detected in the middle of the donut.
Findings show that the researchers did not detect any sign of axions within the mass range of 0.31 to 8.3 nanoelectronvolts in the first month of observations. This means that either axions do not exist within this mass range or axions affect electricity and magnetism even less than scientists previously believed.
While the scientists came up empty in this study, the results do not actually disprove the theory regarding dark matter.
The team is already planning to conduct more ABRACADABRA experiments to search for smaller, weaker axions.
"This is the first time anyone has directly looked at this axion space," Winslow points out. "We're excited that we can now say, 'We have a way to look here, and we know how to do better!'"